Ok so I bought my mac pro in january with applecare (that I had to enroll myself). So when I received it the first thing I did after setting up the mac pro was register my mac pro for applecare, but also I wanted to see if I could add my 23" ACD along with the mac pro's apple care together you know. So I entered the serial number for my 23" ACD then I get some kind of error that wont let me go to the next step so I erased the 23" ACD's serial number and finished registering with applecare for just my mac pro. 3 months later now today, I ordered a apple display applecare from ebay for $40 and today I tried to register my 23" acd and it saids that there is an error so I have to call apple. So before calling apple I entered the serial number for my 23" ACD to verify if it was under apple care and to my surprised its been registered along with my mac pro!! I opened the letter that I received from apple care to verify that the 23" acd was with the mac pro and indeed it was listed there along with my mac pro!! The thing about it is that I only purchased the mac pro + apple care for the mac pro not the 23" ACD. I already owned the 23" ACD for a good 7-8 months before the mac pro purchase.. so I thought it only worked if you bought the mac pro + an ACD at the same time in the same receipt... somehow the system got messed up or I guess it works?? Now I have a opened apple display apple care for 3 years applecare box just sitting at home.. maybe I'll buy that 30" and use that lol.